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Abstract  

Wastes containing radioactive materials have been produced ever since ore recovery and processing began; however, such materials did not become of public concern until the large-scale activities involving uranium and thorium ores and nuclear fission during and after World War II. Efforts to provide disposal sites for radioactive wastes, especially those associated with nuclear weapons and nuclear energy, have been largely unsuccessful for the past 40 years or so and are nearing crisis proportions as the new millennium begins — its eventual resolution is believed to require greater reliance on stewardship and a larger governmental presence.

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W prov a w ll known identity in law b tw n twic the supremum of the B ss l bridg r of dimension 3 and th integral of r -1,using time chang of B ss l bridg s and th agreement formula.W ext nd some computations of laws r lat d to th supremum and th int gral of pow r of r for a bridge of dimension.

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We study the pairs (S,L)of positive random variables which arise in the a .ne de- compositions T (law) =S +L 2 T of the stable

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Abstract  

Thermally Stimulated Current (TSC) spectroscopy and Differential Scanning calorimetry (DSC) have been applied to the characterization of the microstructure of Poly (Ether Ether Ketone)/PEEK. the dielectric relaxation spectra show two modes, dependent upon crystallinity: –  * for the mode stuated in the vicinity of the glass transition temperature, two components have been distinguished and attributed to the molecular mobility in the ‘true amorphous phase’ and in the ‘rigid amorphous region’. –  * below 0°C, two sub-modes appear, situated around-110°C and-75°C, due to the two different crystal entities, beads and laths.

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Abstract  

We show here an adaptation of the classical Flash Method permitting the measure of the thermal conductivity of semi-transparent porous materials. A flash lamp send a heat pulse on the upper face of a cylindrical sample and lower face temperature is analysed. The semi-transparent material is sandwiched between two copper slices. The sample used scatters thermal radiation, and absorbs it very little. It is therefore possible to account for two parts of heat transfer through the material: a pure conductive phenomenon and a radiative one. In most insulating materials radiative transfer represents about 1/3 of the total heat flux at the ambiant temperature. The problem is solved with electrical analogy, quadripoles technique and Laplace transform. The modelization brings out two physical character parameters of the material and a coefficient qualifying the thermal exchange between the sample and the environment during the experiment.

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Abstract  

Fine and coarse particles in suspension in the atmosphere were collected on two Teflon filters with a dichotomous sampler. The concentration of Al, Br, Ca, Ce, Cl, Co, Cr, Fe, K, La, Mn, Na, P, Pb,, S, Sb, Sc, Se, Si, Sm, Th, V and Zn was determined by ED-XRF and INAA. The elemental concentration was analyzed by means of linear correlation coefficients, enrichment factors and principal factors analysis in order to identify the aerosol sources. The main sources of the aerosol particles were the marine ones, resuspended soil, fuel-oil combustion, phosphatic rocks, refuse incineration and residual high-temperature processes.

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Abstract  

A physicochemical study of the systems formed by the clay minerals, montmorillonite and kaolinite (layered) and sepiolite (non-layered) and the surfactants Triton X-100 (TX100, non-ionic), dodecyl sodium sulfate (SDS, anionic) and trimethyloctadecyl-ammonium bromide (ODTMA, cationic), with different chemical structure, was carried out by X-ray diffraction (XRD), infrared spectroscopy (FTIR) and thermogravimetric and differential thermal analysis (TG/DTA). TG/DTA results indicated an increase in the thermal stabilization of non-ionic (TX100) and cationic (ODTMA) surfactants adsorbed by all clay minerals in relation to pure compounds. This effect was greater in montmorillonite and sepiolite than in kaolinite owing to these minerals must allow the establishment of a stronger bond with the surfactants as indicated by XRD and FTIR results. Differences in decomposition of anionic surfactant SDS are not emphasized due to the low adsorbed amount of this surfactant by all systems. The results obtained indicate the interest of taking into account the structure of surfactant and the clay mineral type when preparing customized surfactant-clay mineral systems which contribute to establish more efficient soil and water remediation strategies based in the use of these systems.

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Journal of Thermal Analysis and Calorimetry
Authors: F. J. González-Vila, F. Martin, C. Sáiz-Jiménez, and H. H. Nimz

Thermofractography (TF) has been applied to humic and fulvic acids from four different soil types. Among the thermal products, 3,5-dihydroxybenzoic acid, catechol, 5-hydroxymethylfurfural, vanillin, phenol, furfural, guaiacol and indole were identified. These are typical fragments from lignins, microbial polyphenols, polysaccharides and proteins.

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